1. Field of the Invention
The present invention relates to an electric component transferring apparatus which includes a suction device for sucking and holding, by a negative pressure, an electric component (i.e., component employed in an electric or electronic circuit) and transfers the suction device holding the component, and particularly relates to the art of testing the sucking function of the suction device.
2. Related Art Statement
There is known an electric component ("EC") transferring apparatus which includes (a) at least one suction device which applies a negative pressure ("NP") to an EC and thereby sucks and holds the EC; a suction-device moving device which moves the suction device; and an NP control device which controls the NP supplied to the suction device. The suction device is moved by the suction-device moving device to an EC sucking position, and is supplied with the NP under control of the NP control device. The suction device applies the NP to the EC and thereby sucks and holds the EC. Subsequently, the suction device is moved by the suction-device moving device to transfer the EC and pass the EC to, e.g., an object such as a printed circuit board ("PCB"). When the suction device passes the EC to the PCB, the suction device is communicated with the atmosphere to release the EC. The suction device which applies the NP to the EC can suck and hold the EC without any possibility to damage the EC, unlike an EC holding device which holds an EC with a chuck having a plurality of grasping hands which may damage the EC.
The EC transferring apparatus may include a single suction device or a plurality of suction devices. For example, there is known an EC transferring and mounting apparatus which is employed in an EC mounting system for mounting one or more ECs on a PCB and which includes a movable member, a movable-member moving device for moving the movable member, and one or more suction devices provided on the movable member.
At any rate, the suction device which applies an NP to an EC for sucking up the EC may not apply a sufficiently high NP (i.e., NP having a sufficiently great absolute value) to the EC, for example, if dust or foreign matter enters an NP supply passage in the suction device and clogging occurs to the suction device. In this case, the suction device fails to suck the EC with stability or hold the EC with stiffness. Clogging may occur to not only the passage in the suction device, but also a passage which is provided in a holder head for holding the suction device and which supplies the NP to the suction device, but also a passage which supplies the NP to the holder head. If the suction device has wearing or deformation in a suction surface thereof at which the suction device sucks, the suction surface may not be brought into close contact with the EC, so that the NP may leak from between the suction device and the EC. In this case, too, the suction device cannot apply an appropriate NP to the EC. In the case where the suction device is held by the holder head such that the suction device is slideable relative to the head, and is iteratively slid or moved relative to the head when the suction device sucks ECs, the suction device and the holder head may suffer from wearing at their sliding surfaces, so that NP may leak through the worn surfaces. The leakage of NP may occur because of, e.g., damage of the passage which supplies the NP to the suction device.
Conventionally, an operator applies an NP sensor to the suction device to measure the NP supplied thereto, while the suction device is supplied with the NP. If the NP sensor does not read a sufficiently high NP value, the operator replaces the suction device with another, or takes other appropriate measures. In this way, the suction device is prevented from failing to suck ECs with stability. From the measurement result, the operator should estimate which one of the above-indicated possible causes has lead to the abnormality, and confirm whether his or her estimation is correct.
However, it needs one or more persons to perform the operation of applying the NP sensor to the suction device and measuring the NP supplied thereto. In addition, this operation is very cumbersome for the person or persons. Moreover, this operation may disable full automatization of the EC transferring task as a whole. In particular, in the case where an EC transferring apparatus which has a number of suction devices is used, it is very cumbersome and time-consuming and needs many persons, to apply an NP sensor to each of the suction devices and measure the NP supplied thereto.